#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef double db;

#define in read<int>()
#define lin read<ll>()
#define pii pair<int,int>
#define fi first
#define se second
#define FILE(x) freopen(x".in","r",stdin);\
	freopen(x".out","w",stdout);
#define pb push_back

template <typename T>
T read(){
	T x = 0,sgn = 1;char ch = getchar();
	for(;!isdigit(ch);ch = getchar()) if(ch == '-') sgn = -1;
	for(;isdigit(ch);ch = getchar()) x = (x<<1)+(x<<3)+(ch^48);
	return x*sgn;
}

const int N = 1e4+10;

ll G,X,Y,n,m,k,a[N];

ll mul(ll x,ll y,ll mod){ll res=0;for(;y;y>>=1,x=(x<<1) % mod)if(y&1) res=(res+x)%mod;return res;}

ll gcd(ll x,ll y){return !y ? x : gcd(y,x%y);}

ll lcm(ll x,ll y){return x / gcd(x,y) * y;}

void exgcd(ll a,ll b){
	if(!b){G = a; X = 1;Y = 0;return;}
	exgcd(b,a%b); ll tx = X; X = Y; Y = (tx - a / b * Y);
}

bool Merge(ll x1,ll m1,ll x2,ll m2,ll &x3,ll &m3){
	m3 = lcm(m1,m2); ll t = ((x2 - x1) % m2 + m2) % m2;
	exgcd(m1,m2); if(t % G) return 0;
	X = mul(X,t / G,m2); X += m2; X %= m2; x3 = mul(X,m1,m3) + x1; x3 %= m3; x3 += m3; x3 %= m3;
	return 1;
}

int main (){
#ifndef ONLINE_JUDGE
	freopen("1.in","r",stdin);
#endif
	n = lin,m = lin,k = in;
	ll x = 0,M = 1;
	for(int i = 1;i <= k;i++){
		a[i] = lin;
		if(!Merge(x,M,((a[i] - i) % a[i] + a[i]) % a[i],a[i],x,M)) return puts("NO"),0;
		if(M > n || x > m || x + k > m) return puts("NO"),0;
	}
	for(int i = 1;i <= k;i++) if(gcd(x+i,M) != a[i]) return puts("NO"),0;
	return puts("YES"),0;
	return 0;
}

